The region of the QCD phase diagram
with low temperature and high chemical potential is still not well understood.
From the theoretical point of view, there are no accurate first principles
predictions
for the properties of QCD matter at high baryon densities. The numerical
lattice
simulation techniques that have been successfully applied to the study of the hot
quark gluon plasma (QGP) fail in the cold, baryon rich conditions due to the
sign problem. In spite
of the difficulties, significant progress has been accomplished both in the
theoretical description of moderate density nuclear matter [1]}, [2]}
and ultrahigh-density matter
[3]}, [4]} but no reliable results exist in the crucial regime
between
approximately one and ten nuclear saturation densities. Several model
calculations
suggest that there is a low temperature deconfined phase of quarks and gluons,
the cold QGP, also called quark matter (QM). This phase might exist in the
the core of dense stars, an idea that has been around already for some
decades [5]}, [6]}. It is even possible that a whole star, not only its
core, be made of quark matter [7]}. This possibility was
explored in several works
[8]}, [9]}, [10]}, [11]}, [12]} and will be further
explored in this work, which is an update of [10]}.
